Obscure Audio Software: Wren (Modular soft synth for Windows)

This edition of Obscure Audio Software will focus on another piece of virtual modular gear, though this time the object of our attention is slightly less complex. Today we're going to look at Wren, which is a free and open-source standalone-only modular soft synth (Windows only). It is made by a person known as "bluehell" on the electro-music.com forums.

Just to see if it would work, I tried it in linux (Ubuntu Studio 17) using WINE. Everything seemed to work, and it made sound just fine, but there were graphical glitches with the wires and some other elements, and the pop-up control descriptions refused to go away. This is mentioned on the website, but I figured I'd give it a shot anyway.

Main interface window with some modules patched up.

What kind of bird is this?

Wren is basically a software version of a modular synthesizer. It is similar in many ways to pretty much any other modular-type synth, though it includes many unusual modules. According to the author: "Wren is not a product, but a hobby project that got out of control a bit. This software ain't good for anything and it will crash your PC too." I wouldn't agree with the first part of that second sentence, nor have I experienced any crashes, but ymmv, as they say. There are a few "known issues" posted on the website, but I wouldn't say any of them are really game-ending.

Those minor foibles aside, Wren is truly fantastic in my opinion, especially for freeware. The modules include all of the stuff you might expect as standard for modular synths: oscillators, filters, envelopes, VCA's, etc., but even among those there are some interesting entries, such as the "Attractor" oscillator, which uses a "strange attractor" formula based on either the Lorenz or Rössler function to generate sound (or LFO signals), or the "Tod" LFO, which gives the current time of day as a value ranging from zero to one in hour, minute, second, or millisecond increments (so basically a sawtooth LFO with a frequency of 24 hours). There are also several types of random and algorithmic generators and sequencers, such as a couple types of cellular automaton, a sequencer based on Conway's Game of Life, and a logistic map module. Some other highlights include speech synthesis, granulator effects, and a convolution-based vocoder. These are just some examples, there is a full list with descriptions on the website (link below).

Modules are loaded either from icons in the top menu bar, or by right-clicking and choosing from a drop-down menu. You connect them together using virtual wires, which are color-coded by function (audio signal, control signal, logic signal, etc.). You can even use custom colors for the wires. Some modules are "rate smart", meaning they can tell whether they are recieving audio-rate or control-rate (or whatever) signals, and adjust automatically. Connection points are marked with either a circle or a square, to denote inputs and outputs, respectively. You can disconnect single wires or whole "wire trees" with a right-click on the connector.

Other than the modules/synthesis features, Wren also includes some other nice touches, such as a built-in audio recorder, a patch randomizer, morphing features, and a search function to find modules by name in case you have a large or otherwise hard-to-follow patch. I'm quite impressed with the "quality of life" features like this that are included, again, especially for freeware.

The radomization/mutator window.

There are a couple of features that don't seem to be implemented yet, though they appear in the interface, one being recording and playback for parameter automation. Another is "abstractions", which according to the website is some sort of "patch as a module" thing. Perhaps some type of sub-patch kind of thing? Both of those would be nice, but it doesn't ruin the experience not having them. Development seems to be fairly active for a one-man labor of love though, so these features may be implemented before long. There is a note on the website that the automation recorder is being rewritten, so that at least is definitely in the works.

Wren can use PortAudio for low-latency audio performace, or "legacy" wave in/out, and supports multiple channels of audio I/O (fun for patching in external hardware gear). It supports MIDI using NetMIDI. Wren also supports OSC.

Settings page.

Free bird

All in all, I think Wren is worth a try for anyone with a Windows machine who is interested in modular synthesis, and since it's free, what do you have to lose? Even if you already have other modular stuff to play with, Wren has enough unusual features that I think it would be a valuable addition to your arsenal.

Thanks for checking out this installment of Obscure Audio Software! Feel free to comment below, either about this article or Wren itself, or something else you think would make a good subject for a future edition of Obscure Audio Software.